Photos: Red Spot Jr. grows on Jupiter

The Great Red Spot is a storm on Jupiter that has been raging for at least 400 years. Three Earths can fit into the storm, which is similar to a hurricane. The storm was active when humans first observed the planet with a telescope.

Astronomers do not know why the Red Spot is red, but one theory says that the storms scoop up red materials from beneath Jupiter's clouds.

Photo by Credit: NASA, ESA, I. de Pater and M. Wong/University of California at Berkeley